The present invention generally relates to a process and apparatus for making articles, and particularly to a process and apparatus for making disposable absorbent articles.
Various products are fabricated in a continuous production line by the sequential addition of components to previously supplied components. This is particularly advantageous when one or more of the components can be supplied in the form of a single continuous layer. For example, in the formation of disposable absorbent articles, such as training pants, diapers, incontinence articles, feminine care products, or the like, a layer is normally supplied at a point in the fabrication line in the form of a continuous roll, and absorbent pads, waist elastic bands, leg elastic bands, stretchable side panels, and/or other components can be supplied at different points in the fabrication line as discrete elements.
Various processes and apparatus are available for bringing the components of a single product together so that the components in the composite product are in a desired relation with respect to each other. In bringing these components properly together, various known processes and apparatus are used to note the position of a particular component, and then to adjust the placement of subsequent components in order to properly position them.
A problem encountered with these methods and apparatus is that they do not adequately compensate for a material to be registered, for example a continuously moving layer of material, having a repeat length greater than the machine product repeat length. Consequently, during the manufacturing process, when a material having a uniform repeat length greater than a machine product repeat length is fed through the apparatus to be registered with a material having a shorter length corresponding to the machine product repeat length, the excess material uncontrollably slacks and thus results in machine wrap-ups.